https://doi.org/10.1140/epjb/e2003-00034-6
The high-pressure α/β phase transition in lead sulphide (PbS)
X-ray powder diffraction and quantum mechanical calculations
Christian-Albrechts-Universität zu Kiel, Institut für
Geowissenschaften, Mineralogie/Kristallographie, Olshausenstr. 40,
24098 Kiel, Germany
Corresponding author: a knorr@min.uni-kiel.de
Received:
11
October
2002
Published online:
14
February
2003
The high-pressure behaviour of
PbS was investigated by angular dispersive X-ray powder diffraction
up to pressures of 6.8 GPa. Experiments were accompanied by first
principles calculations at the density functional theory level. By
combining both methods reliable data for the elastic properties of
rock-salt type α- and high-pressure β-PbS could be
obtained. β-PbS could be determined to crystallise in the
CrB-type (B33), with space group Cmcm. The reversible
ferro-elastic α/β transition is of first order. It is
accompanied by a large volume discontinuity of about 5% and a
coexistence region of the two phases. A gliding mechanism of {001}
bilayers along one of the cubic 
directions
governs the phase transition which can be described in terms of
group/subgroup relationships via a common subgroup, despite its
reconstructive character. The quadrupling of the primitive unit cell
indicates a wave vector 
on the Δ-line of the
Brillouin zone.
PACS: 91.60.Gf – High-pressure behaviour / 61.50.Ks – Crystallographic aspects of phase transformations; pressure effects / 77.84.Bw – Elements, oxides, nitrides, borides, carbides, chalcogenides / 62.20.Dc – Elasticity, elastic constants
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2003
